Late Quaternary vegetational history of the Black River region in northeastern Alaska

1988 ◽  
Vol 25 (1) ◽  
pp. 84-94 ◽  
Author(s):  
Patricia M. Anderson ◽  
Richard E. Reanier ◽  
Linda B. Brubaker
Keyword(s):  
Picea Glauca ◽  
Late Quaternary ◽  
Major Change ◽  
Migration Route ◽  
Herbaceous Species ◽  
Geographical Patterns ◽  
Pollen Diagrams ◽  
River Region ◽  
Shrub Tundra ◽  
History Of

Two pollen diagrams describe the previously unknown vegetational history of the Black River and Little Black River drain ages of northeastern Alaska. Tundra grew throughout much of the region between ca. 19 800 and 15 000 years BP. Prior to 18 000 years BP, the vegetation was dominated perhaps by xeric Cyperaceae communities, but apparently between ca. 18 000 and 15 000 years BP a more diverse herb tundra characterized the vegetation. Herbaceous species continued to be important in the vegetation until ca. 9700 years BP, although Betula nana–glandulosa and Salix species became more common after 15 000 years BP. At ca. 9700 years BP a major change in the vegetation occurred with the spread of Populus (probably P. balsamifera), B. nana–glandulosa, and Salix, possibly resulting in a mosaic of shrub tundra and Populus gallery forest. Picea glauca migrated into the Black River region ca. 7500 years BP, followed by Alnus ca. 7200 years BP and Picea mariana ca. 6000 years BP.Herb zone records from the Black River region support the hypothesis that eastern Beringian vegetation was characterized by a tundra mosaic prior to 14 000 years BP. Chronological and geographical patterns in the Populus subzone from eastern Beringia suggest that the expansion of Populus populations may not have been exclusively in response to climate change. Dates of Picea arrival on the western Porcupine Plateau indicate that this area probably was not an early Holocene migration route for Picea.

Modern Pollen Assemblages and Vegetational History of the Moraines of the Klutlan Glacier and Its Surroundings, Yukon Territory, Canada

1980 ◽  
Vol 14 (1) ◽  
pp. 101-129 ◽  
Author(s):  
H. J. B. Birks
Keyword(s):  
Picea Glauca ◽  
Yukon Territory ◽  
Canonical Variate ◽  
Pollen Diagram ◽  
Modern Pollen ◽  
Canonical Variates ◽  
Shrub Tundra ◽  
History Of ◽  
Shepherdia Canadensis ◽  
Modern Pollen Assemblages

AbstractModern pollen assemblages have been studied from surficial lake muds and moss polsters collected from five vegetated ice-cored moraines of the Klutlan Glacier. The youngest vegetated moraine (K-II) is characterized by high pollen values for Salix and Hedysarum, K-III by high Salix and Shepherdia canadensis and low Hedysarum and Picea, K-IV by high Betula, Salix, and Shepherdia, and K-V and the Harris Creek moraine (HCM) by high Picea. Variations are summarized by canonical variates analysis. A percentage pollen diagram from Gull Lake on the upland east of the glacier records vegetational development since the deposition of the White River volcanic ash 1220 14C yr ago. An initial species-rich treeless vegetation was replaced by birch-alder-willow shrub-tundra, and this by open Picea glauca forest similar to present vegetation around the lake. Sites on HCM show two basic stratigraphies. Triangle Lake reflects vegetational succession from Salix-Shepherdia canadensis scrub similar to that on K-III today, through open Picea woodland of K-IV type, to closed Picea forests of K-V and HCM. Heart Lake and Cotton Pond reflect vegetational development following melting of ice underlying the spruce forests of HCM. These two types are summarized by positioning the fossil spectra on the first two canonical variate axes of the modern surface spectra.

Late Quaternary Pollen Records from the Kobuk and Noatak River Drainages, Northwestern Alaska

1988 ◽  
Vol 29 (3) ◽  
pp. 263-276 ◽  
Author(s):  
Patricia M. Anderson
Keyword(s):  
Picea Glauca ◽  
Regional Differences ◽  
Late Quaternary ◽  
Limited Effect ◽  
Local Expansion ◽  
Thermal Maximum ◽  
Pollen Diagrams ◽  
Northern Alaska ◽  
River Drainages ◽  
Pollen Records

Pollen diagrams from Joe and Niliq Lakes date to ca. 28,000 and 14,000 yr B.P., respectively. Mesic shurb tundra grew near Joe Lake ca. 28,000 to 26,000 yr B.P. with localPopuluspopulations prior to ca. 27,000 yr B.P. Shrub communities decreased as climate changed with the onset of Itkillik II glaciation (25,000 to 11,500 yr B.P.), and graminoid-dominated tundra characterized vegetation ca. 18,500 to 13,500 yr B.P. Herb tundra was replaced by shrubBetulatundra near both sites ca. 13,500 yr B.P. with local expansion ofPopulusca. 11,000 to 10,000 yr B.P. andAlnusca. 9000 yr B.P. MixedPicea glauca/P. marianawoodland was established near Joe Lake ca. 6000 yr B.P. These pollen records when combined with others from northern Alaska and northwestern Canada indicate (1) mesic tundra was more common in northwestern Alaska than in northeastern Alaska or northwestern Canada during the Duvanny Yar glacial interval (25,000 to 14,000 yr B.P.); (2) with deglaciation, shrubBetulaexpanded rapidly in northwestern Alaska but slowly in areas farther east; (3) an early postglacial thermal maximum occurred in northwestern Alaska but had only limited effect on vegetation; and (4) pollen patterns in northern Alaska and northwestern Canada suggest regional differences in late Quaternary climates.

Problems of inertia and threshold related to post-Glacial habitat changes

1965 ◽  
Vol 161 (984) ◽  
pp. 331-342 ◽  
Keyword(s):  
Late Quaternary ◽  
Great Distance ◽  
Radiocarbon Age ◽  
Habitat Changes ◽  
Pollen Zone ◽  
Relative Chronology ◽  
Pollen Diagrams ◽  
Circular Argument ◽  
History Of

Most of the major late-Quaternary vegetational changes deduced from the study of pollen diagrams have generally been supposed to have been brought about by climatic change. The assumption has also been made that widespread climatically controlled vegetational changes are likely to have been broadly synchronous (cf. for instance Godwin 1956, p. 57). Recently, however, it has become clear that differences of migration rate and the rates of pedogenesis should be given more attention; Faegri, in particular, has made this point very strongly with reference to the history of the Scandinavian flora (Faegri 1963). In addition, it is appropriate to note that Iversen (1960, p. 9) has questioned whether we can attach any climatic significance to the pollen zone transitions up to the beginning of the Atlantic period and whether they will prove to be synchronous over any great distance. Nevertheless, the assumption that the well-marked vegetational changes in a small area such as the British Isles are likely to have been synchronous has sufficed to allow the establishment of a useful relative chronology for archaeological and other purposes. While the radiocarbon age estimations so far obtained do not on the whole confute the assumptions, there are a number of exceptions (cf. Godwin 1960; Godwin & Willis 1959, 1962; McAulay & Watts 1961, etc.). For phytogeographical purposes, however, it is clearly to argue in a circle to use a chronology based on vegetational evidence; we must equally be on our guard against the circular argument in discussing the role of habitat changes in palaeoecology.

Late Quaternary History of Tundra Vegetation in Northwestern Alaska

1994 ◽  
Vol 41 (3) ◽  
pp. 306-315 ◽  
Author(s):  
Patricia M. Anderson ◽  
Patrick J. Bartlein ◽  
Linda B. Brubaker
Keyword(s):  
Vegetation Type ◽  
Late Quaternary ◽  
Vegetation Types ◽  
The Past ◽  
Modern Pollen ◽  
Qualitative Approaches ◽  
Tundra Vegetation ◽  
Shrub Tundra ◽  
History Of ◽  
Quaternary History

AbstractPollen analysis of a new core from Joe Lake indicates that the late Quaternary vegetation of northwestern Alaska was characterized by four tundra and two forest-tundra types. These vegetation types were differentiated by combining quantitative comparisons of fossil and modern pollen assemblages with traditional, qualitative approaches for inferring past vegetation, such as the use of indicator species. Although imprecisely dated, the core probably spans at least the past 40,000 yr. A graminoid-Salix tundra dominated during the later and early portions of the glacial record. The middle glacial interval and the transition from glacial to interglacial conditions are characterized by a graminoid-Betula-Salix tundra. A Populus forest-Betula shrub tundra existed during the middle potion of this transition, being replaced in the early Holocene by a Betula-Alnus shrub tundra. The modern Picea forest-shrub tundra was established by the middle Holocene. These results suggest that the composition of modem tundra communities in northwestern Alaska developed relatively recently and that throughout much of the late Quaternary, tundra communities were unlike the predominant types found today in northern North America. Although descriptions of vegetation variations within the tundra will always be restricted by the innate taxonomic limitations of their herb-dominated pollen spectra, the application of multiple interpretive approaches improves the ability to reconstruct the historical development of this vegetation type.

Palynology of six sections of Late Quaternary sediments from the Old Crow River, Yukon Territory

1973 ◽  
Vol 51 (3) ◽  
pp. 553-564 ◽  
Author(s):  
Sigrid Lichti-Federovich
Keyword(s):  
Late Quaternary ◽  
Yukon Territory ◽  
Quaternary Sediments ◽  
Pollen Assemblage ◽  
Alluvial Deposits ◽  
Pollen Stratigraphy ◽  
Tundra Vegetation ◽  
Pollen Diagrams ◽  
Shrub Tundra ◽  
Basin Fill

The Old Crow Plain, northern Yukon Territory, Canada, is a large flat lowland consisting of basin-fill sediments of Late Quaternary age. The modern Arctic treeline passes across the northern tip of the lowland, and much of the vegetation consists of tundra and shrub tundra, with scattered groves of spruce mainly on alluvial deposits. Steep scarps have been exposed by the downcutting of the Old Crow River in these basin-fill sediments, and good exposures of Late Quaternary sediments are available for investigation. Samples from six of these exposures were analyzed for pollen. Although many parts of the sections were barren, it has been possible to derive pollen diagrams with discrete pollen zones for the six sections, and four pollen assemblage types have been identified. Their occurrence in the stratigraphie sequence suggests the following pattern of pollen stratigraphy: the lowermost sedimentary units, probably deposited early in the interstadial following an Early Wisconsin glaciation, are of pollen assemblage types III (Glumiflorae–herb) or IV (Betula–herb), both indicative of tundra vegetation; the middle levels of the sediment show, consistently, pollen spectra of type II (Picea–Betula–Glumiflorae–herb), indicating forest groves with tundra, quite similar to the modern vegetation. The sediment underlying the Upper Glaciolacustrine Unit (correlative, according to Hughes (1969), with the Classical Wisconsin Stadial) yields pollen assemblage type III (Glumiflorae–herb), which is interpreted as indicating a rich and varied tundra. These vegetation reconstructions are consonant with a tentative palaeoclimatic interpretation in terms of a tripartite interstadial climate showing severe tundra climate – milder forest or forest–tundra climate – severe tundra climate. Two of the sections have incomplete pollen stratigraphy for the uppermost postglacial silts and peats. They suggest that vegetation similar to the present day became established in the Old Crow Plain in mid-postglacial time.

The late quaternary history of the Cumberland lowland

1966 ◽  
Vol 251 (770) ◽  
pp. 1-210 ◽  
Keyword(s):  
Late Quaternary ◽  
Human Settlement ◽  
Pollen Diagrams ◽  
History Of ◽  
Quaternary History

The geography and geology and history of human settlement of the Cumberland Lowland is decribed and the choice of sites for the investigation of the vegetational history of the region discussed in relation to these factors. The principles underlying the presentation and zonation of the pollen diagrams are set out.

scholarly journals Late Quaternary Pollen Records and Vegetation History of the Southwest Yukon Territory: A Review

2007 ◽  
Vol 45 (2) ◽  
pp. 175-193 ◽  
Author(s):  
Xia-Cheng Wang ◽  
Marie-Anne Geurts
Keyword(s):  
Vegetation History ◽  
Late Quaternary ◽  
Late Glacial ◽  
Yukon Territory ◽  
Circulation System ◽  
Spruce Forest ◽  
Migration Routes ◽  
Shrub Tundra ◽  
History Of ◽  
Pollen Records

ABSTRACTThis paper is a summary of all known late Quaternary palynostratigraphic records from the southwest Yukon Territory. Thirty two pollen sites available by the end of 1988 are reviewed. Most pollen records in the region are of Holocene age. During the late-glacial to early Holocene, the southwest Yukon supported a herb-dominated tundra vegetation which was replaced by a birch-dominated shrub-tundra at about 10,000 yr BP. Spruce invaded the area between 9000 and 8600 yr BP at different localities, and a southward time transgression is visible in the Aishihik Basin. The current regional vegetation has been stable since 7600-8000 yr BP when dense spruce forest and/or spruce forest-tundra was established in most localities. In the Snag area, however, dense spruce forest developed only around 5700 yr BP, which is about 2000 years later than in the Aishihik Basin. The exotic pine pollen records in the region exhibit an interesting pattern, suggesting a frequent shift of the atmospheric circulation system. Anomalous records of alder pollen from the Aishihik Basin and adjacent regions suggest that alder has never been widespread in these areas due to aridity, and alder pollen is greatly overrepresented in pollen spectra. Spruce arrival dates suggest that further investigations in the Tintina Valley, Yukon River Valley, and Car-macks region might provide useful information concerning the spruce migration routes.

Late Quaternary Vegetation of Southern Isla Grande De Chiloé, Chile

1988 ◽  
Vol 29 (3) ◽  
pp. 294-306 ◽  
Author(s):  
Carolina Villagran
Keyword(s):  
Climatic Change ◽  
Pollen Analysis ◽  
Tree Species ◽  
Late Quaternary ◽  
Late Glacial ◽  
Pollen Diagrams ◽  
History Of ◽  
Valdivian Forest ◽  
Nothofagus Dombeyi ◽  
Pollen Records

Late-glacial-Holocene forest history of southern Isla Chiloé (latitude 43°10′ S) was reconstructed on the basis of pollen analysis in three profiles (Laguna Soledad, Laguna Chaiguata, Puerto Carmen). Prior to 12,500 yr B.P. pollen records are dominated by plant taxa characteristic of open habitats (Zone I). From 12,500 yr B.P. to the present, tree species predominate in the pollen records (Zones II–V). Between 12,500 and 9500 yr B.P. ombrophyllous taxa (Nothofagus, Podocarpus nubigena. Myrtaceae, Fitzroya/Pilgerodendron, and Drimys) are frequent in all pollen diagrams, suggesting a wetter and colder climate than the present. Between 9000 and 5500 yr B.P. Valdivian forest elements, such as Nothofagus dombeyi type, Weinmannia, and Eucryphia/Caldcluvia, dominate, indicating a period of drier and warmer climate. From 5500 yr B.P. onward, the expansion of mixed North Patagonian-Subantarctic forest elements and the increased frequence of Tepualia suggest increased rainfall and temperatures oscillating around the modern values.The change from open to forest vegetation (ca. 12,500 yr B.P.) probably represents the most pronounced climatic change in the record and can be interpreted as the glacial-postglacial transition in the study area.

A 14,000-Year Pollen Record from Sithylemenkat Lake, North-Central Alaska

1990 ◽  
Vol 33 (3) ◽  
pp. 400-404 ◽  
Author(s):  
Patricia M. Anderson ◽  
Richard E. Reanier ◽  
Linda B. Brubaker
Keyword(s):  
Boreal Forest ◽  
Sediment Core ◽  
Pollen Analysis ◽  
Picea Glauca ◽  
Pollen Record ◽  
North Central ◽  
The Holocene ◽  
Unusual Combination ◽  
Shrub Tundra ◽  
History Of

AbstractPollen analysis of a 14,000-yr-old sediment core from Sithylemenkat Lake provides the first Holocene vegetational history for the Kanuti Flats of north-central Alaska. Basal samples contain a curious and unusual combination of tundra and boreal taxa. Pollen assemblages dating from 13,500 to 9000 yr B.P. are more typical of southern Brooks Range sites and indicate the presence ofBetulashrub tundra with increasedPopulusca. 10,000 to 9000 yr B.P.Picea glaucaappeared ca. 9000 yr B.P. andAlnusca. 8000 yr B.P.P. glaucapopulations declined between 7800 and 5000 yr B.P. with a subsequent reforestation byP. marianaandP. glauca. This pattern is seen at other sites in northeastern Alaska and suggests that the Holocene history of boreal forest is more complex than thought previously.

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